DIVISION II.
On the DECOMPOSITION of NITROUS OXIDE by COMBUSTIBLE BODIES. Its ANALYSIS. OBSERVATIONS on the different combinations of OXYGENE and NITROGENE.
I. Preliminaries.
From the phænomena mentioned in [Res. I. Divis. III].[166] it appears that the combustible bodies burn in nitrous oxide at certain temperatures. The experiments in this Division were instituted for the purpose of investigating the precise nature of these combustions, with a view of ascertaining exactly the composition of nitrous oxide.
It will be seen hereafter that very high temperatures are required for the decomposition of nitrous oxide, by most of the combustible bodies, and that in this process heat and light are produced to a very great extent. These agents alone are possessed of a considerable power of action on nitrous oxide; of which it is necessary to give an account, that we may be able to understand the phænomena in the following sections.
II. Conversion of Nitrous Oxide into Nitrous Acid,
and a Gas analogous to Atmospheric Air, by Ignition.
a. Dr. Priestley asserts, that nitrous oxide exposed for a certain time to the action of the electric spark, is rendered immiscible with water, and capable of diminution with nitrous gas, without suffering any alteration of volume; and likewise that the same changes are effected in it by exposure to ignited incombustible bodies.[167]
The Dutch chemists state, that the electric spark passed through nitrous oxide, occasions a small diminution of its volume, and that the gas remaining is analogous to common air.[168] They conclude that this change depends on the separation of its constituent parts, oxygene and nitrogene, from each other.
None of these chemists have suspected the production of nitrous acid in this process.
b. Nitrous oxide undergoes no change whatever from the simple action of light. I exposed some of it, confined by mercury, for many days to this agent, often passing through it concentrated rays by means of a small lens. When examined it appeared, as well as I could estimate, of the same degree of purity as at the beginning of the experiment.
c. A temperature below that of ignition effects no alteration in the constitution of nitrous oxide. I passed nitrous oxide from a retort containing decomposing nitrate of ammoniac, through a green glass tube, strongly heated in an air-furnace, but not suffered to undergo ignition. The gas, received in a water apparatus exhibited the same properties as the purest nitrous oxide; some of it absorbed by water, left a residuum of not quite one thirteenth.
d. The action of the electric spark for a long while continued, converts nitrous oxide into a gas analogous to atmospheric air, and nitrous acid.
I passed about 150 strong shocks from a small Leyden phial, through 7 ten grain measures of pure nitrous oxide. After this it filled a space rather less than six measures: the mercury was rendered white on the top, as if it had been acted on by nitric acid. Six measures of nitrous gas mingled with the residual gas of the experiment, over mercury covered by a little water, gave red fumes, and rapid diminution. In five minutes the volume of the gases nearly equalled ten. Thermometer in this experiment was 58°.
Electric sparks were passed for an hour and half through 7 ten grain measures of nitrous oxide over mercury covered with a little red cabbage juice, previously saturated with nitrous oxide, and rendered green by an alkali. After the process the gas filled a space equal to rather more than six measures and half, and the juice was become of a pale red. The gas was introduced into a small tube filled with pure water, and agitated; no absorption was perceptible: 7 measures of nitrous gas added to it gave red fumes, and after six minutes a diminution to 9¼ nearly. 6½ measures of common air from the garden, with 7 of nitrous gas, gave exactly 9.
In this experiment it was evident that nitrous oxide was converted into a gas analogous to atmospheric air, at the same time that an acid was formed. There could be little doubt but that this was the nitrous acid. To ascertain it, however, with greater certainty, the electric spark was passed through 6 measures of nitrous oxide, over a little solution of green sulphate of iron, confined by mercury. As the process went on, the color of the solution became rather darker. When the diminution was complete, a little prussiate of iron was added to the solution. A precipitate of pale blue prussiate of potash was produced.
c. Nitrous oxide was passed from decomposing nitrate of ammoniac, through a porcelain tube well glazed inside and outside, strongly ignited in an air-furnace, and communicating with the water apparatus. The gas collected was rendered opaque by dense red vapor. It appeared wholly unabsorbable by water. After the precipitation of its vapor, a candle burnt in it with nearly the same brilliancy as in atmospheric air. 20 measures of it that had been agitated in water immediately after its production, mingled with 40 measures of nitrous gas, diminished to about 47.5; whereas 20 measures that had remained unagitated for some time after their generation, introduced to the same quantity of nitrous gas, gave nearly 49. 20 measures of atmospheric air, with 40 of the same nitrous gas, were condensed to 46.
The water with which the gas had been in contact, was strongly acid. A little of it poured into a solution of green sulphate of iron, and then mingled with prussian alkali, produced a green precipitate. Hence the acid it contained was evidently nitrous.
That no source of error could have existed in this experiment from fissure in the tube, I proved, by sending water through it whilst ignited, after the process, from the same retort in which the nitrate of ammoniac had been decomposed; a few globules of air only were produced, not equal to one tenth of the volume of the water boiled, and which were doubtless previously contained in it.
I have repeated this experiment two or three times, with similar results; whenever the air was agitated in water immediately after its production, it gave almost the same diminution with nitrous gas as common air; when, on the contrary, it has been suffered to remain for some time in contact with the phlogisticated nitrous acid suspended in it, the condensation has been less with nitrous gas by five or six hundred parts. Hence I am inclined to believe, that if it were possible to condense all the nitrous acid formed, immediately after its generation, so as to prevent it from absorbing oxygene from the permanent gas, this gas would be found identical with the air of the atmosphere.
The changes effected by fire on nitrous oxide are not analogous to those produced by it in other bodies; for the power of this agent seems generally uniform, either in wholly separating the constituent principles of bodies from each other, or in making them enter into more intimate union.[169]
It is a singular phænomenon, that whilst it condenses one part of the oxygene and nitrogene of nitrous oxide, in the form of nitrous acid; it should cause the remainder to expand, in the state of atmospheric air. Does not this fact afford an inference in favor of the chemical composition of atmospheric air?
III. Decomposition of Nitrous Oxide by Hydrogene,
at the temperature of Ignition.
In the following experiments on the decomposition of nitrous oxide by hydrogene, the gases were carefully generated in the mercurial apparatus, and their purity ascertained by the tests mentioned in [Research I]. They were measured in small tubes graduated to grains, and then transferred into the detonating tube, which was eight tenths of an inch in diameter, and graduated to ten grain measures.
The space occupied by the gases being noted after the inflammation by the electric shock, green muriate of iron, and prussiate of potash, were successively introduced, to ascertain if any nitrous acid had been formed. The absorption, if any took place, was marked, and the gases transferred into a narrow grain measure tube, and their bulk and composition accurately ascertained.
b. The hydrogene employed was procured from water by means of zinc and sulphuric acid. 50 grain measures of it fired by the electric spark, with 30 grain measures of oxygene containing one eleventh nitrogene, gave a residuum of about 4. Nitrous gas mingled with those 4, indicated the presence of rather less than 1 of unconsumed oxygene. In another experiment 23 of it, with 20 of the same oxygene left rather more than 6 residuum.
The nitrous oxide was apparently pure, for it left a remainder of about ,05 only, when absorbed by common water.
c. 30 of hydrogene were fired with 40 of nitrous oxide; the concussion was very great, and the light given out bright red; no perceptible quantity of nitrous acid was formed; the residual gas filled a space equal to 52. No part of it was absorbable by water, it gave no diminution with nitrous gas, when it was mingled with a little oxygene, and again acted on by the electric spark, an inflammation and slight diminution was produced.
d. 33 of hydrogene were fired with 35 of nitrous oxide: nitrous acid was produced in very minute quantity; the gas that remained was not absorbable by water, and filled a space equal to 37 grains. Nitrous gas mingled with these, underwent a very slight diminution.
e. 46 hydrogene were fired with 46 nitrous oxide. The quantity of nitrous acid formed was just sufficient to tinge the white prussiate of potash. The gases filled a space equal to 49, gave no perceptible diminution with nitrous gas, and did not inflame with oxygene.
f. 40 hydrogene were fired with 39 nitrous oxide; no perceptible quantity of nitrous acid was formed. The residual gas filled a space equal to 41; was unabsorbable by water, underwent no diminution when mingled with nitrous gas; or when acted on by the electric spark in contact with oxygene.
g. 20 hydrogene were fired with 64 nitrous oxide; after detonation the expansion of the gases was greater in this experiment than any of the preceding ones; dense white fumes were observed in the cylinder, and a slow contraction of volume took place. After a little green muriate of iron had been admitted, the gases filled a space equal to 73: prussiate of potash mingled with the muriate, gave a deeper blue than in any of the preceding experiments. The residual gas was unabsorbable by water: 65 of it, mingled with 65 of nitrous gas, diminished to 93; whilst 65 of common air, with 65 of nitrous gas, gave 84.
h. 8 of hydrogene were fired with 54 of nitrous oxide; the same phænomena as were observed in the last experiment took place; nitrous acid was formed; after the absorption of which the residual gas filled a space equal to 55. 50 of this, with an equal quantity of nitrous gas, diminished to 76. In these processes the temperatures were from 56° to 61°.
These experiments are selected as the most accurate of nearly fifty, made on the inflammation of different quantities of nitrous oxide and hydrogene.
As Mr. Keir found muriatic acid in the fluid, produced by the inflammation of oxygene and hydrogene in closed vessels, in Dr. Priestley’s experiments, I preserved the residual gas of about 3 cubic inches of nitrous oxide, that had been detonated at different times with less than a cubic inch and half of hydrogene; but solution of nitrate of silver was not clouded when agitated in this gas, nor when introduced into the detonating tube in which the inflammation had been made.
From these experiments we learn that nitrous oxide is decomposable at the heat of ignition, by hydrogene, in a variety of proportions.
When the quantity of hydrogene very little exceeds that of the nitrous oxide, both of the gates disappear, water is produced, no nitrous acid is formed, and the volume of nitrogene evolved is rather greater than that of the nitrous oxide decomposed.
When the quantity of hydrogene is less than that of the nitrous oxide, water, nitrous acid, oxygene and nitrogene, are generated in different proportions; one part of the nitrous oxide is most probably wholly decomposed by the hydrogene, and the other part converted into nitrous acid and atmospheric air, in consequence of the ignition.
From experiments c, d, and e, the composition of nitrous oxide may be deduced. In experiment d, 39 of nitrous oxide were decomposed by 40 of hydrogene, and converted into 41 of nitrogene.
Now from b it appears that 40 of hydrogene require for their condensation about 20.8 of oxygene in volume; so that founding the estimation upon the quantity of hydrogene consumed, 100 parts of nitrous oxide would consist nearly of 63.1 of nitrogene, and 36.9 of oxygene. But 41 of nitrogene weigh 12.4, [Res. I. Div. I]. Consequently, deducing the composition of nitrous oxide from the quantity of nitrogene evolved, 100 parts of it would consist of 63.5 nitrogene, and 36.5 oxygene.
These estimations are very little different from those which may be deduced from the other experiments, and the coincidence is in favor of their accuracy.
From the following experiment it appears that the temperature required for the decomposition of nitrous oxide by hydrogene must be higher than that which is necessary to produce the inflammation of hydrogene with oxygene. I introduced into small tubes filled with equal parts of nitrous oxide and hydrogene, standing on a surface of mercury, iron wires ignited to different degrees, from the dull red to the vivid white heat. The gases were always inflamed by the white and vivid red heats; but never by the dull red heat, though the last uniformly inflamed mixtures of oxygene and hydrogene, and atmospheric air and hydrogene.
Dr. Priestley[170] first detonated together nitrous oxide and hydrogene; his experiment was repeated by the Dutch chemists, who found that when a small quantity of hydrogene was employed, the nitrous oxide was partially converted into a gas analogous to common air. Their estimation of its composition, which is not far removed from the truth, was founded on this phænomenon.[171]
IV. Decomposition of Nitrous Oxide by Phosphorus.
a. Phosphorus introduced into pure nitrous oxide at common temperatures, is not at all luminous. It is capable of being fused, and even sublimed in it, without undergoing acidification, and without effecting any alteration in its composition.
About 2 grains of phosphorus were fused, and gradually sublimed, in 2 cubic inches of pure nitrous oxide, over mercury, by the heat of a burning lens. No alteration was produced in the volume of gas, and a portion of it absorbed by water, left a residuum of one twelfth only.
Phosphorus was sublimed in pure nitrous oxide over mercury, in a dark room, by an iron heated nearly to ignition; but no luminous appearance was perceptible, nor was any gas decomposed.
b. Phosphorus decomposes nitrous oxide at the temperature of ignition, with greater or less rapidity, according to the degree of heat. We have already seen, that when phosphorus in active inflammation is introduced into nitrous oxide, it burns with intensely vivid light.
Phosphorus was sublimed by a heated wire in a jar filled with nitrous oxide, standing over warm mercury. In this state of sublimation an iron heated dull red was introduced to it by being rapidly passed through the mercury; a light blue flame surrounded the wire, and disappeared as soon as it ceased to be red.
To phosphorus sublimed as before, in nitrous oxide, over warm mercury, a thick wire ignited to whiteness was introduced; a terrible detonation took place, and the jar was shattered in pieces.
By employing thick conical jars,[172] containing only a small quantity of nitrous oxide, I effected the detonation several times with safety; but on account of the great expansion of the elastic products, the jar was generally either raised from the mercury, or portions of gas were thrown out of it. Hence I was unable to ascertain the exact changes produced by this mode of decomposition.
c. As my first attempts to ascertain the constitution of nitrous oxide were made on its decomposition by phosphorus, I employed many different modes of partially igniting this substance in it over mercury, so as to produce a combustion without explosion.
The first method adopted was inflammation by means of oxygenated muriate of potash. A small particle of oxygenated muriate of potash was inserted into the phosphorus to be burnt. On the application of a wire, moderately hot, to the point of insertion, the salt was decomposed by the phosphorus, and sufficient fire generated and partially applied by the slight explosion, to produce the combustion of the phosphorus, without the previous sublimation of any part of it.
The second way employed was the ignition of a part of the phosphorus, by means of the combustion of a small portion of tinder of cotton,[173] or paper, in contact with it, by the burning glass.
The third, and most successful mode, was by introducing into the graduated jar containing the nitrous oxide, the phosphorus in a small tube containing oxygene, so balanced as to swim on the surface of the mercury, without communicating with the nitrous oxide. The phosphorus was fired in the oxygene with an ignited iron wire, by which at the moment of combustion, the tube containing it was raised into the nitrous oxide, and thus the inflammation continued.
d. In different experiments, made with accuracy, I found that the whole of a quantity of nitrous oxide was never decomposable by ignited phosphorus; the combustion always stopped when the nitrous oxide remaining was to the nitrogene evolved as about 1 to 5; likewise that the volume of nitrogene produced was rather less than that of the nitrous oxide decomposed, and that this deficiency arose from the formation of nitrous acid by the intense ignition produced during the process.
Of one experiment I shall give a detail.
Temperature being 48°, two cubic inches of pure nitrous oxide, which had been generated over mercury, were introduced into a jar of the capacity of 9 cubic inches, graduated to,1 cubic inches, and much enlarged at the base. A grain of phosphorus was inserted into a small vessel about one third of an inch long, and half an inch in diameter, containing about 15 grain measures of very pure oxygene; this vessel, which swam on the surface of the mercury, was carefully introduced into the jar containing the nitrous oxide. The phosphorus was fired by means of a heated wire, and before the oxygene was wholly consumed, the vessel containing it elevated into the nitrous oxide. The combustion was extremely vivid and rapid. After the atmospheric temperature was restored, the gas was rendered opaque by dense white vapor. When this had been precipitated, and the small vessel removed from the jar, the gas filled a space nearly equal to 1.9 cubic inches. On introducing to it a little solution of green muriate of iron, and prussiate of potash, green prussiate of iron was produced: hence, evidently, nitrous acid had been formed.
On the admission of pure water, an absorption of rather more than,3 took place.
The 16 measures remaining underwent no perceptible diminution with nitrous gas; the taper plunged into them was instantly extinguished.
To ascertain if the phosphoric acid produced in the experiments made under mercury did not in some measure prevent the decomposition of the whole of the nitrous oxide by the phosphorus, I introduced into a mixture of 5 nitrogene and 1 nitrous oxide, ignited phosphorus: but it was immediately extinguished.[174]
The Dutch Chemists found that phosphorus might be fused in nitrous oxide without being luminous. They assert that phosphorus in a state of inflammation, introduced into this gas, was immediately extinguished; though when taken out into the atmosphere, it again burnt of its own accord.[175] It is difficult to account for their mistake.
V. Decomposition of Nitrous Oxide by
Phosphorated Hydrogene.
a. It has been mentioned in [Res. II. Div. I]. that phosphorated hydrogene and nitrous oxide posses no action on each other, at atmospheric temperatures.
Phosphorated hydrogene mingled with nitrous oxide, is capable of being inflamed by the electric spark, or by ignition.
b. E. 1. 10 grain measures of phosphorated hydrogene, carefully produced by means of phosphorus and solution of caustic alkali, were mingled with 52 measures of nitrous oxide. The electric spark passed through them, produced a vivid inflammation. The elastic products were clouded with dense white vapor, and after some minutes filled a space nearly equal to 60. On the introduction of water, no absorption took place. When 43 of nitrous gas were admitted, the whole diminished to 70.
E. 2. 25 of nitrous oxide were fired with 10 of phosphorated hydrogene, by the electric spark. After detonation[176] they filled a space exactly equal to 25. On the admission of solution of green sulphate of iron, and prussiate of potash, no blue or green precipitate was produced. On the introduction of water, no diminution was perceived. 25 of nitrous gas mingled with them, gave exactly 50.
E. 3. 10 of nitrous oxide, mingled with 20 of phosphorated hydrogene, could not be inflamed.
25 of nitrous oxide, with 20 phosphorated hydrogene, inflamed. The gas after detonation, was rendered opaque by dense white vapor, and filled a space nearly equal to 45. No absorption took place when water was introduced. On admitting a little oxygene no white fumes, or diminution, was perceived. The electric spark passed through the mixture, produced an explosion, with great diminution.
c. From E. 1 it appears, that when a small quantity of phosphorated hydrogene is inflamed with nitrous oxide, both the phosphorus and hydrogene are consumed; whilst the superabundant nitrous oxide, is converted into nitrous acid and atmospheric air, by the ignition; or a certain quantity is partially decomposed into atmospheric air by the combination of a portion of its oxygene with the combustible gas.
From E. 2 we learn, that when the phosphorated hydrogene and nitrous oxide are to each other as 25 to 10 nearly, they both disappear, whilst nitrogene is evolved, and water and phosphoric acid produced. Reasoning concerning the composition of nitrous oxide from this experiment, we should conclude that it was composed of about 38 oxygene, and 62 nitrogene.
The result of E. 3 is interesting; we are taught from it that the affinity of phosphorus for the oxygene of nitrous oxide is stronger than that of hydrogene, at the temperature of ignition; so that when phosphorated hydrogene is mingled with a quantity of nitrous oxide, not containing sufficient oxygene to burn both its constituent parts, the phosphorus only is consumed, whilst the hydrogene is liberated.
In repeating the experiments with phosphorated hydrogene that had remained for some hours in the mercurial apparatus, I did not gain exactly the same results; for a larger quantity of it was required to decompose the nitrous oxide, than in the former experiments; doubtless from its having deposited a portion of its phosphorus. They confirm, however, the above mentioned conclusions.
In the course of experimenting, I passed the electric spark, for a quarter of an hour, through about 60 measures of phosphorated hydrogene. It underwent no alteration of volume. Phosphorus was apparently precipitated from it, and it had wholly lost its power of inflaming, in contact with common air.
VI. Decomposition of Nitrous Oxide by Sulphur.
From the phænomena before mentioned,[177] relating to the combustion of sulphur in nitrous oxide, it was evident that this gas was only decomposable by it, at a much higher temperature than common air.
I introduced into sulphur in contact with nitrous oxide, over mercury heated to 112°-114°, a wire intensely ignited. It lost much of its heat in passing through the mercury, but still appeared red in the vessel. The sulphur rapidly fused, and sublimed without being at all luminous. This experiment was repeated five or six times, but in no instance could the combustion of sulphur, by means of the ignited wire, be effected.
I inflamed sulphur in nitrous oxide in the same manner as phosphorus; namely, by introducing it into the small vessel filled with oxygene, and igniting it by means of the heated wire. In these experiments the sulphur burnt with a vivid rose-colored light, and much sulphuric, with a little sulphureous acid, was formed.
Experimenting in this way I was never, however, able to decompose more than one third of the quantity of nitrous oxide employed; not only the nitrogene evolved, but likewise the sulphuric and sulphureous acids produced, stopping the combustion.
I found that sulphur in a state of vivid inflammation, when introduced into a mixture of one fourth nitrogene, and three fourths nitrous oxide, burnt with a flame very much enlarged, and of a vivid rose color. In one third nitrogene, and two thirds nitrous oxide, it burnt feebly with a yellow flame. In equal parts of nitrous oxide and nitrogene, it was instantly extinguished.
Sulphur burnt feebly, with a light yellow flame, when introduced ignited into a mixture of 5 nitrous gas, and 6 nitrous oxide. In one third nitrous oxide, and two thirds nitrous gas, it was instantly extinguished. From many circumstances, I am inclined to believe that sulphur is incapable, at any temperature, of slowly decomposing nitrous oxide, so as to burn in it with a blue flame, forming sulphureous acid alone. It appears to attract oxygene from it only when intensely ignited, so as to form chiefly sulphuric acid, and that with great rapidity, and vivid inflammation.
VII. Decomposition of Nitrous Oxide by
Sulphurated Hydrogene.
a. Though nitrous oxide and sulphurated hydrogene do not act upon each other at common temperatures, yet they undergo a mutual decomposition when mingled together in certain proportions, and ignited by the electric spark.
From more than twenty experiments made on the inflammation of sulphurated hydrogene in nitrous oxide, I select the following as the most conclusive and accurate. The temperature at which they were made was from 41° to 49°.
b. E. 1. About 35 measures of nitrous oxide were fired with 10 of sulphurated hydrogene; the expansion during inflammation was very great, and the flame sky-blue. Immediately after, the gases filled a space equal to 48 nearly. White fumes were then formed, and they gradually contracted to 40. On the admission of a little strontian lime water, a slight absorption took place, with white precipitation; and the volume occupied by the residual gas nearly equalled 37. On admitting nitrous gas to these, no perceptible diminution took place.
E. 2. 20 sulphurated hydrogene, with 25 nitrous oxide, could not be inflamed.
30 nitrous oxide, with 22 sulphurated hydrogene, could not be inflamed.
35 nitrous oxide, with 20 sulphurated hydrogene, inflamed with vivid blue light, and great expansion. After the explosion, the gases filled exactly the same space as before the experiment; no white fumes were perceived, and no farther contraction occurred. On the addition of strontian lime water, a copious precipitation, with diminution, took place; and the residual gas filled a space nearly equal to 35½.
E. 3. 47 nitrous oxide, and 14 sulphurated hydrogene, inflamed. After the explosion, the gases filled a space nearly equal to 65; then white fumes formed, and they gradually diminished to 52. On the introduction of muriate of strontian, a copious white precipitate was produced; and on the addition of water, no further absorption took place. To the residual 52, about 20 of nitrous gas were added; they filled together a space equal to about 67.
c. In none of the experiments made on the inflammation of sulphurated hydrogene and nitrous oxide, could I ascertain with certainty the precipitation of sulphur. In one or two processes the detonating tube was rendered a little white at the points of contact with the mercury; but this was most probably owing to the oxydation of the mercury, either by the heated sulphuric acid formed, or from nitrous acid produced by the ignition. The presence of nitrous acid I could not ascertain in these processes by my usual tests, because the combustion of sulphur over white prussiate of iron, converts it into light green.
When I introduced an inflamed taper into about 3 parts of sulphurated hydrogene, and 2 parts of nitrous oxide, in which proportions they could not have been fired by the electric spark, a blue flame passed through them, and much sulphur was deposited on the sides of the vessel. But this sulphur most probably owed its formation to the decomposition of a portion of sulphurated hydrogene not burnt, by the sulphureous acid formed from the combustion of the other portion.
We may then conclude with probability, that sulphurated hydrogene and nitrous oxide will not decompose each other, when acted on by the electric spark, unless their proportions are such as to enable the whole of the sulphurated hydrogene to be decomposed, so that both of its constituents may become oxygenated, by attracting oxygene from the nitrous oxide: likewise, that when the sulphurated hydrogene is at its maximum of inflammation, the hydrogene and sulphur form with the whole of the oxygene of nitrous oxide, water and sulphureous acid; E. 2: whereas at its minimum they produce water, and chiefly, perhaps wholly, sulphuric acid; at the same time that the nitrous oxide partially decomposed, is converted into nitrogene, and a gas analogous to atmospheric air, or into nitrogene, nitrous acid, and atmospheric air. E. 1. E. 3.
By pursuing those experiments, and using larger quantities of gas, we may probably be able to ascertain from them with accuracy, the composition of sulphuric and sulphureous acids.
I own I was disappointed in the results, for I expected to have been able to ascertain from them, the relative affinities of sulphur, and hydrogene for the oxygene of nitrous oxide, at the temperature of ignition. I conjectured that nitrous oxide, mingled with excess of sulphurated hydrogene, would have been decomposed, and one of the principles of it evolved unaltered, as was the case with phosphorated hydrogene.
If we estimate the composition of nitrous oxide from the quantity of nitrogene produced in E. 2, it is composed of about 61 nitrogene, and 39 oxygene.
VIII. Decomposition of Nitrous Oxide by Charcoal.
An account of the analysis of nitrous oxide by charcoal is given in [Res. I. Div. III]. I have lately made two experiments on the combustion of charcoal in nitrous oxide, in which every precaution was taken to prevent the existence of sources of error. Of one of these I shall give a detail.
E. Temperature being 51°, about a grain of charcoal, which had been exposed for some hours to a red heat, was introduced whilst ignited, under mercury, and transferred into a graduated jar, containing 3 cubic inches of pure nitrous oxide, standing over dry mercury.
The focus of a burning lens was thrown on the charcoal; it instantly inflamed, and burnt with great vividness for near a minute, the gas being much expanded. The focus was continually applied to it for ten minutes, when the process appeared at an end. The gases, when the common temperature and pressure were restored, filled a space equal to 4,2 cubic inches.
On introducing into them a few grain measures of solution of green muriate of iron, for the double purpose of saturating them with moisture, and ascertaining if any nitrous acid had been formed, no change of volume took place; and prussiate of potash gave with the muriate a white precipitate only.
On the admission of a small quantity of concentrated solution of caustic potash, a diminution of the gas slowly took place; when it was complete the volume equalled about 3.05 cubic inches. By agitation in well boiled water, about,9 of these were absorbed; the remainder appeared to be pure nitrogene.
The difference between the estimation founded upon the nitrogene evolved, and that deduced from the carbonic acid generated in this experiment, is not nearly so great as in that [Res. I. Div. III]. Taking about the mean proportions, we should conclude that nitrous oxide was composed of about 38 oxygene, and 62 nitrogene.
Charcoal burnt with greater vividness than in common air, in a mixture of one third nitrogene and two thirds nitrous oxide. In equal parts of nitrous oxide and nitrogene, its light was barely perceptible. In one third nitrous oxide, and two thirds nitrogene, it was almost immediately extinguished.
As charcoal burns vividly in nitrous gas, when it has been previously ignited to whiteness, I introduced it into a mixture of equal parts of nitrous oxide and nitrous gas; it burnt with a deep and bright red.
IX. Decomposition of Nitrous Oxide
by Hydrocarbonate.
Nitrous oxide, and hydrocarbonate, possess no action on each other, except at high temperatures. When mingled in certain proportions, and exposed to the electric shock, a new arrangement of their principles takes place.
E. 1. Temperature being 53°, 35 of nitrous oxide, mingled with 15 of hydrocarbonate, were fired by the electric spark; the inflammation was very vivid, and the light produced, bright red. After the explosion, the space occupied by the gases equalled about 60. On the admission of solution of strontian, a copious white precipitate was produced, and the gas diminished by agitation, to rather more than 35. When 36 of nitrous gas were added to these, white fumes appeared and the whole diminished to 62. When a little muriatic acid was poured on the white precipitate from the solution of strontian, gas was evolved from it, and it was gradually dissolved.
E. 2. 22 nitrous oxide were inflamed with 20 hydrocarbonate; after the explosion, they filled a space equal to 45; when strontian lime water was introduced, white precipitation took place, and the diminution was to 31.
To these 31, 14 of nitrous oxide were admitted, and the electric spark passed through them; an inflammation took place: carbonic acid was formed, after the absorption of which, the gas remaining filled a space equal to 43, and did not diminish with nitrous gas.
The hydrocarbonate employed in these experiments, was procured from alcohol by means of sulphuric acid. In another set of experiments made with less accuracy, the same general results were obtained. Whenever hydrocarbonate inflamed with nitrous oxide, both its constituents were oxygenated; in all cases carbonic acid was formed, and in no instance free hydrogene evolved, or charcoal precipitated.
In the decomposition of nitrous oxide by hydrocarbonate, the residual nitrogene is less than in other combustions. This circumstance I am unable to explain.
Reasoning from analogy, there can be little doubt, but that when hydrocarbonate is inflamed with excess of nitrous oxide, it will be only partially decompounded, or converted into nitrogene, nitrous acid, and atmospheric air.
The Dutch Chemists have asserted, that charcoal does not burn in nitrous oxide, except in consequence of the previous decomposition of the gas by the hydrogene always contained in this substance; and likewise, that when hydrocarbonate and nitrous oxide were mingled together, and fired by the electric spark, the hydrogene only was burnt, whilst the charcoal was precipitated.
It is difficult to account for these numerous mistakes. Their theory of the non-respirability of nitrous oxide was founded upon them. They supposed that the chief use of respiration was to deprive the blood of its superabundant carbon, by the combination of atmospheric oxygene with that principle; and that nitrous oxide was highly fatal to life, because it was incapable of de-carbonating the blood[178]!!
X. Combustion of Iron in Nitrous Oxide.
I introduced into a jar of the capacity of 20 cubic inches, containing 11 cubic inches of nitrous oxide, over mercury, a small quantity of fine iron wire twisted together, and having affixed to it a particle of cork. On throwing the focus of a burning glass on the cork, it instantly inflamed, and the fire was communicated to the wire, which burnt with great vividness for some moments, projecting brilliant white sparks. After it had ceased to burn the gas was increased in volume rather more than three tenths of an inch. The nitrous acid tests were introduced, but no acid appeared to have been formed. On exposing the gas to water, near 4,2 cubic inches were absorbed: the 7,1 remaining appeared to be pure nitrogene.
From this experiment it is evident that iron at the temperature of ignition, is capable of decomposing nitrous oxide; likewise that it is incapable of burning in it when it contains more than three fifths nitrogene.
I attempted to inflame zinc in nitrous oxide, in the same way as iron; but without success. By keeping the focus of a burning glass upon some zinc filings, in a small quantity of nitrous oxide, I converted a little of the zinc into white oxide, and consequently decomposed a portion of the gas.
XI. Combustion of Pyrophorus in Nitrous Oxide.
Pyrophorus, which inflames in nitrous gas, and atmospheric air, at or even below 40°, requires for its combustion in nitrous oxide a much higher temperature. It will not burn in it, or alter it, even at 212°.
I have often inflamed pyrophorus in nitrous oxide over mercury, by means of a wire strongly heated, but not ignited. The light produced by the ignition of pyrophorus in nitrous oxide is white, like that produced by it in oxygene: in nitrous gas it is red.
When pyrophorus burns out in nitrous oxide, a little increase of the volume of gas is produced. Strontian lime water agitated in this gas becomes clouded; but the quantity of carbonic acid formed is extremely minute. I have never made any delicate experiments on the combustion of pyrophorus in nitrous oxide.
XII. Combustion of the Taper in Nitrous Oxide.
It has been noticed by different experimentalists, that the taper burns with a flame considerably enlarged in nitrous oxide: sometimes with a vivid light and crackling noise, as in oxygene; at other times with a white central flame, surrounded by a feeble blue one.
My experiments on the combustion of the taper in nitrous oxide, were chiefly made with a view to ascertain the cause of the double flame.
When the inflamed taper is introduced into pure nitrous oxide, it burns at first with a brilliant white light, and sparkles as in oxygene. As the combustion goes on, the brilliancy of the flame diminishes; it gradually lengthens, and becomes surrounded with a pale blue cone of light, from the apex of which much unburnt charcoal is thrown off, in the form of smoke. The flame continues double to the end of the process.
When the residual gases are examined after combustion, much nitrous acid is found suspended in them; and they are composed of carbonic acid, nitrogene, and about one fourth of undecompounded nitrous oxide.
The double flame depends upon the nitrous acid formed by the ignition; for it can be produced by plunging the taper into common air containing nitrous acid vapor, or into a mixture of nitrous oxide and nitrogene, through which nitrous acid has been diffused. It is never perceived in the combustion of the taper, till much nitrous acid is formed.
In attempting to respire some residual gas of nitrous oxide, in which a taper had burnt out, I found it so highly impregnated with nitrous acid, as to disable me from even taking it into my mouth.
The taper burns in a mixture of equal parts nitrous oxide and nitrogene, at first with a flame nearly the same as that of a candle in common air; white. Before its extinction the interior white flame, and exterior blue flame, are perceived.
The taper is instantly extinguished in a mixture of one fourth nitrous oxide, and three fourths nitrogene.
In a mixture of equal parts nitrous oxide and nitrous gas, the taper burns at first with nearly as much brilliancy as in pure nitrous oxide; gradually the double and feeble flame is produced.
XIII. On the Combustion of different
Compound Bodies in Nitrous Oxide.
All the solid and fluid compound inflammable bodies on which I have experimented, burn in nitrous oxide, at high temperatures. Wood, cotton, and paper, are easily inflamed in it by the burning glass. During their combustion, nitrous acid is always formed, carbonic acid, and water produced, and nitrogene evolved, rather less in bulk than the nitrous oxide decomposed.
I have already mentioned that alcohol and ether are soluble in nitrous oxide. When an ignited body is introduced into the solution of alcohol, or ether in nitrous oxide, a slight explosion takes place.
XIV. General Conclusions relating to the Decomposition
of Nitrous Oxide, and to its Analysis.
From what has been said in the preceding sections, it appears that the inflammable bodies, in general, require for their combustion in nitrous oxide, much higher temperatures than those at which they burn in atmospheric air, or oxygene.
When intensely heated they decompose it, with the production of much heat and light, and become oxygenated.
During the combustion of solid or fluid bodies, producing flame, in nitrous oxide, nitrous acid is generated, most probably from a new arrangement of principles, analogous to those observed in Sect. II, by the ignition of that part of the gas not in contact with the burning substance. Likewise when nitrous oxide in excess is decomcomposed by inflammable gases, nitrous acid, and sometimes a gas analogous to common air, is produced, doubtless from the same cause.
Pyrophorus is the only body that inflames in nitrous oxide, below the temperature of ignition.
Phosphorus burns in it with the blue flame, probably forming with its oxygene only phosphoreous acid at the dull red heat, and with the intensely vivid flame, producing phosphoric acid at the white heat.
Hydrogene, charcoal, sulphur, iron, and the compound inflammable bodies, decompose it only at heats equal to, or above, that of ignition: probably each a different temperature.
From the phænomena in Sect. V. it appears, that at the temperature of intense ignition, phosphorus has a stronger affinity for the oxygene of nitrous oxide than hydrogene; and reasoning from the different degrees of combustibility of the inflammable bodies, in mixtures of nitrous oxide and nitrogene, and from other phænomena, we may conclude with probability, that at about the white heat, the affinity of the combustible bodies for oxygene takes place in the following order. Phosphorus, hydrogene, charcoal,[179] iron, sulphur, &c.
This order of attraction is very different from that obtaining at the red heat; in which temperature charcoal and iron have a much stronger affinity for oxygene than either phosphorus or hydrogene.[180]
The smallest quantity of oxygene given in the different analyses of nitrous oxide just detailed, is thirty five hundred parts; the greatest proportion is thirty-nine.
Taking the mean estimations from the most accurate experiments, we may conclude that 100 grains of the known ponderable matter of nitrous oxide, consist of about 36,7 oxygene, and 63,3 nitrogene; or taking away decimals, of 37 oxygene to 63 nitrogene; which is identical with the estimation given in [Research I].
XV. Observations on the combinations of
Oxygene and Nitrogene.
During the decompositions of the combinations of oxygene and nitrogene by combustible bodies, a considerable momentary expansion of the acting substances, and the bodies in contact with them is generally produced, connected with increased temperature; whilst light is often generated to a great extent.
Of the causes of these phænomena we are at present ignorant. Our knowledge of them must depend upon the discovery of the precise nature of heat and light, and of the laws by which they are governed. The application of general hypotheses to isolated facts can be of little utility; for this reason I shall at present forbear to enter into any discussions concerning those agents, which are imperceptible to the senses, and known only by solitary effects.
Analysis and synthesis clearly prove that oxygene and nitrogene constitute the known ponderable matter of atmospheric air, nitrous oxide, nitrous gas, and nitric acid.
That the oxygene and nitrogene of atmospheric air exist in chemical union, appears almost demonstrable from the following evidences.
1st. The equable diffusion of oxygene and nitrogene through every part of the atmosphere, which can hardly be supposed to depend on any other cause than an affinity between these principles.[181]
2dly. The difference between the specific gravity of atmospheric air, and a mixture of 27 parts oxygene and 73 nitrogene, as found by calculation; a difference apparently owing to expansion in consequence of combination.
3dly. The conversion of nitrous oxide into nitrous acid, and a gas analogous to common air, by ignition.
4thly. The solubility of atmospheric air undecompounded in water.
Atmospheric Air, then, may be considered as the least intimate of the combinations of nitrogene and oxygene.
It is an elastic fluid, permanent at all known temperatures, consisting of,73 nitrogene, and,27 oxygene. It is decomposable at certain temperatures, by most of the bodies possessing affinity for oxygene. It is soluble in about thirty times its bulk of water, and as far as we are acquainted with its affinities, incapable of combining with most of the simple and compound substances. 100 cubic inches of it weigh about 31 grains at 55° temperature, and 30 atmospheric pressure.
Nitrous Oxide is a gas unalterable in its constitution, at temperatures below ignition. It is composed of oxygene and nitrogene, existing perhaps in the most intimate union which those substances are capable of assuming.[182] Its properties approach to those of acids. It is decomposable by the combustible bodies at very high temperatures, is soluble in double its volume of water, and in half its bulk of most of the inflammable fluids. It is combinable with the alkalies, and capable of forming with them peculiar salts. 100 grains of it are composed of about 63 nitrogene, and 37 oxygene. 100 cubic inches of it weigh 50 grains, at 55° temperature, and 30 atmospheric pressure.
Nitrous Gas is composed of about,56 oxygene, and,44 nitrogene, in intimate union. It is soluble in twelve times its bulk of water, and is combinable with the acids, and certain metallic solutions; it is possessed of no acid properties, and is decomposable by most of the bodies that attract oxygene strongly, at high temperatures. 100 cubic inches of it weigh about 34 grains, at the mean temperature and pressure.
Nitric Acid is a substance permanently aëriform at common temperatures, composed of about 1 nitrogene, to 2,3 oxygene. It is soluble to a great extent in water, and combinable with the alkalies, and nitrous gas. It is decomposable by most of the combustible bodies, at certain temperatures. 100 cubic inches of it weigh, at the mean temperature and pressure, nearly 76 grains.